Engine starter



April 25, 1933. J. w. Frrz GERALD ENGINE STARTER Original Filed lay 19.1928 www Patented pr. 25,

UNITED STATES PATENT OFFICE JOHN W. FITZ GERALD, 0F MILVAUKEE,WISCONSIN, ASSIGNOR T0 BRIGGS & STRATTON CORPORATION, OF MILWAUKEE,WISCONSIN, A CORPORATION 0F DELAWARE ENGINE STARTER Original applicationfiled May 19, 1928, Serial No. 279,174. Divided and this applicationfiled July 15,

1931. Serial This invention relates to starters for automobile engines,marine engines, airplane engines and the like, and is a division ofLetters PatentNo. 1,804,757.

It is an object of this invention to provide an improved starter ofsimplified construction to reduce production costs and, at the sametime, provide a more eflicientand practical structure.

The starters now in common use arek substantially as illustrated in theBritish patent to Galloway, et al., No. 6,824 of 1884, wherein a piniongear is adapted to be thrown into mesh with a ring gear preferably xedto the engine fly wheel when the starting motor is operated and adaptedto be disengaged therefrom upon the speed of the engine iy wheelbecoming greater than that of the starter motor. This structure is notcomplete and hence not practical in that should the teeth of the gearsfail to be in register when they engage, breakage results and in LettersPatent No. 1,116,137 O, issued Vincent Bendix, November 10, 1914, ayieldable drive connection for the starter gear shaft permits thenecessary give7 should the teeth of the gears fail to mesh.

The latter structure is open to mechanical objections, as the springcrystallizes from constant use and when broken the entire starter isVinoperative and this invention has as another object the provision of astarter for engines wherein the starter shaft is in substantially onepiece and has means for permitting the desired give in the event thegears fail to properly mesh instantly upon the starter gear engaging theengine gear.

A more speciiic object of this invention resides in the provision of animproved starter for engines wherein the drive unit is yieldable axiallyunder stress in the event the teeth of the starter gear fail to alignwith the teeth of the engine gear instantly upon their engagement.

lVith the above and other objects in View which will appear as thedescription proceeds, my invention resides in the. novel construction,combination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the append- No. 550,863. f

ed claims, it being understood that such changes in the preciseembodiment of the hereindisclosed invention may be made as come withinthe scope of the claims.

In the accompanying drawing, I have illustrated several completeexamples of the physical embodiment of my invention constructedaccording to the best modes I have so far devised for the practicalapplication of the principles thereof, and in which:

Figure 1 is a view, partly in side elevation and partly in section, ofan electric starting motor embodying one form of my invention; and

Figure 2 is a view similar to Figure 1 illustrating a slightly modifiedform of my invention.

Referring now more particularly to the accompanying drawing, in whichlike nulmerals designate like parts throughout the several views, 5designates an electric motor of suitable design and constructionincluding a rotor 6 having its shaft 7 journaled in bearings 8 atopposite ends of the motor housing 9. One end of shaft 7 projects beyondthe housing and is provided with an enlargement 10 which is fastthereto' and may be integral therewith if desired and is provided withexternal helical threads 11 on` which a 'pinion 12 is threaded.

In that form of my invention illustrated in Figure 1, whichis theout-board type of starter, the shaft 7 is preferably provided with abearing support 13 positioned at the side of the 'engine ring gearliopposite to the starter motor. The ring gear 14 is preferably carriedby the fiy wheel 15 of the engine, not shown, and as the rotor 6 isrotated by the closing of the motor circuit, not shown, the helicalthreads 11 cause the pinion 12 to be advanced axially and engage thegear' 14 of the motor, its engagement with thegear 141 being limited bya shoulder or collar 16 and its movement inwardly being restricted by ashoulder or a stop 17.

In the event the teeth of the pinion and ring gear fail to mesh as theyengage, it is necessary that either the rotation or axial movement ofthe starter gear bek momentarily arrested until the teeth register. Itis in this particular, that the structure illustrated in the Britishpatent to Galloway fails, and this invention provides means forpermitting the starter pinion to yield axially by mounting the entiremotor unit so as to yield axially. Obviously various diierent means formounting the motor housing may be employed and the drawing illustratesbut tivo preferable. arrangements.

ln Figure l, the motor housing O is provided with a base lcl Ywhich re.s on a mounting bracket l5) of approximae y right-angular construction,having a horizontal motor supporting Wall Q0 and an upright end Wall 2l.This bracket may be supported from the engine structure not shovvn inany suitable manner. The motor supporting Wall 20 thereof is providedwith a plurality ot elongated openingor slots .22 through whichattaching bolts Q25 carried by the motor base 18 pass to secure themotor to the mounting bracket.

The motor is thus slidable on Jdie bracket for the length el" the slots2, but is yieldahly urged to one iimit oi movement by an expansivespring -leon'ined betr-:een the upright Wall and tue adjacent end ol themotor, the spring 24- being maintained in position by a lug 26 extendedfrom the end wall 2l, and by havingl its opposite end received in apoclret QT iormed in the end wall 25 ot the motor.

lf the teeth oi the gears fail to register during] operation, the entiremotor unit moves axially against the action oi the spring 24 until the.teeth oit the pinion i2 and the ring gear l align. when the spring Ziwill move the unit to the right with reference to the drawing and thegear l2 will continue its advance toits fully meshed position.

Figure 2 illustrates this invention as applied to starters of theiii-board type. In this modification the housing oi the motor 5 is ofuniform cylindrical shape throughout and is slidably mounted in an outercasing or sleeve Q8 in which it is held against rotary movement byelongated keys or guides 29 formed on the inner Wall ot' the casing 28and slidably received in suitable guide Ways in the motor housing. Anexpansive spring 30 coniined between the end ivall 3l of the casing 2Sand the adjacent end 32 of the motor yieldably urges the motor in onedirection.

The operation of this form ot the invention is substantiallyT identicalYith that shown in Figure l except that the direction of axial movementof the motor and also of the drive pinion is reversed.

From the foregoing description taken in connection With the accompanyingdrawing, it will be readily apparent to one skilled in the art to whichan invention of the character described appertains, that by mounting theentire motor unit for axial movement to yield in the event ofmisa-ligament of the driving pinion with the teeth of the ring gear, thedesired yielding act-ion in starters of this type is obtained in thesimplest possible manner and hence, the production cost is greatlyreduced. It is also readily apparent that starters constructed inaccordance with this invention are etlicient in operation and embody apractical design.

'hat I claim as my invention is:

l. An engine starter, comprising the, combination with a. memberoperatively connected With an engine, a motor, a rotatable member, a.driving member mounted to travel longitudinally on said rotatable memberinto engagement with said engine member and also to rotate therewith,means mounting the motor for axial movement, and means yieldablyresisting axial movementof the motor in a direction opposed to thedirection of movement of the driving member to engage the engine member.

2. The combination with an electric motor including a rotor shaft and adrive member on the shaft engageable with a member to be driven, ofmeans mounting the motor to aceoinmoda te axial movement thereof, meansyield-ably resisting axial movement of the motor in one. direction, andcooperating means carried by the rotor shaft and the drive member formoving' the motor against said yielding means to preclude destruction ofthe driving member or the member to be driven upon improper engagementof the driving member with the member to be driven.

3. The combination with an electric motor including a rotor shaft and adriving member on the shaft engageable with a. member to be driven, of amounting member for the motor,

means attaching said motor to the mounting member so as to accommodatelimited axial movement of the motor, yieldable means resisting axialmovement of the motor in one direction and normally maintaining the samein its opposite limit of movement, and cooperating means carried by thedriving member and the motor shaft and operable to engage the drivingmember with the member to be driven and to move the motor axiallyagainst the yielding means in the event of improper engagement of thedriving mem- 3er with the member to be driven to preclude destruction ofthe driving member and the member to be driven.

4. In an engine starter, the combination with a member to be drivenoperatively connected with an engine, of a motor including a rotor, adrive member carried by the rotor and engageable with the member to bedriven, said drive member normally being disen` gaged from the member tobe driven, screw means carried by the drive member and the motor rotor'for advancing the drive member towards the member to be driven uponoperation oi the motor, means mounting the means for the motor enablinglimited axial movement of the motor and its rotor as a unit and holdingthe motor against rotation, and means yieldably resisting axial movementof the motor in a direction opposite to the direction of movement of thedriving pinion to engage the gear member.

6. In an engine starter, the combination with a gear member associatedwith an engine, of a starting motor including a rotor, a driving pinion,means carried by the rotor and the driving pinion and operable uponoperation of the starting motor to move the driving pinionlongitudinally along the rotor into engagement with the gear member andto drive the gear member through the pinion upon complete engagementtherewith, a

Vmounting member for the starting motor,

means attaching the starting motor to said mounting member so as toenable limited axial movement of the motor as a whole, and an expansivespring confined between one end of the motor and a fixed abutmentyieldably resisting axial movement of the motor in a direction opposedto the direction of the movement of the driving pinion to engage theengine gear member.

7. In an engine starter, the combination with a gear member operativelyconnected with an engine, of a starting motor having a rotor, a drivingpinion carried by the rotor, means carried by thefdriving pinion and therotor and operable to engage the pinion with the gear member uponoperation of the starting motor and to drive the gear. member uponcomplete engagement therewith, a mounting bracket having elongated slotswhose longitudinal axes are parallel with the axis of the motor,attaching screws passing through part of the motor and received in saidslots whereby the motor is mounted for limited axial movement, and anexpansive spring confined between one end of the motor and part ofr saidmounting bracket to yieldably oppose axial movement of the motor in adirection opposite to the movement of the driving pinion towards thegear member and to yield upon improper engagement of the drive pinionwith the gear member so as to preclude injury to either the drive pinionor the gear member.

8. In an engine starter of the character described, the combination witha gear member operatively connected with an engine, of a starting motorhaving a rotor, a driving pinion on the rotor, means carried by thedriving pinion and the rotor and operable to engage the driving pinionwith the gear member upon operation of the motor and to drive the gearmember through the pinion upon complete engagement thereof, a stationarysupporting housing receiving the starting motor :tor axial slidingmovement, means carried by said mounting housing and the starting motorto prevent rotation of the starting motor in said housing, and anexpensive spring coniined between the starting motor and one wall ofsaid supporting housing to yieldably oppose axial movement of thestarting motor in one directionfand to yield upon improper engagement ofthe pinion with the gear member so as to preclude injury to the gearmember or the pinion.

In testimony whereof I have hereunto afiixed my signature.

JOHN W. FITZ GERALD.

